1. Field of the Invention
The present invention relates to a technology for generating analytical models used in numerical analysis of object shape models, and particularly relates to generation of simplified analytical models.
2. Description of the Related Art
In recent object shape design, a designing process has been effectively performed by generating an analytical model (mesh model) for numerical analysis of an object shape using modeling data (object shape data, three-dimensional CAD data) so that the time required for the generation is reduced.
For example, VPS/Simulation-HUB (manufactured by Fujitsu Ltd.) referred to in below non-Patent Reference 1 has a function for converting three-dimensional (hereinafter abbreviated to 3D) CAD data into an analytical model (a mesh structure).
FIGS. 21(a), 21(b) and 21(c) are perspective views illustrating an analytical model generated in a conventional analytical model generating method: FIG. 21(a) is a perspective view of an example of an object shape model generated by 3D CAD; FIG. 21(b) is a perspective view illustrating an example of an analytical model generated based on the object shape model of FIG. 21(a) in a conventional generating method; and FIG. 21(c) is an enlarged view illustrating a part of the analytical model of FIG. 21(b) The example of the analytical model shown in FIGS. 21(b) and 21(c) takes the form of cuboid meshes (also called orthogonal meshes).
A conventional analytical model generating method generates a large number of meshes to represent a curved portion or the like as shown in FIG. 21(c). Specifically, generation of an analytical model based on modeling data generated by means of 3D CAD results in a large number of small meshes for a curved portion or a line in order to represent the shape of the modeling data in high fidelity, so that mesh information (the number of divisions) becomes large.
As a consequence, an analytical model of a mobile telephone or a laptop computer, whose surface has many curved portions due to a design aspect, tends to be large in data scale.
For example, the analytical model of FIGS. 21(b) and 21(c) is large in scale with more than 50 million meshes. [Non-Patent Reference] UEDA, Akira URAKI, Yasushi and AOKI, Kenichiro: “High-Speed Modeling of VPS/Simulation-HUB”, FUJITSU, vol. 55, No. 3 (May 2004).
However, since it is said that analytical scale (time required for an analysis process) is proportional to the square of the number of meshes, analysis (numerical analysis) using solver (an analytical tool) is not practically performed on a large-scale analytical model generated in the conventional method in view of limitations on performance of a computer. For this reason, minor changes in the shape of an analytical model are unavoidable.
As an example of the solution to the above problem, concerning the analytical model shown in FIGS. 21(b) and 21(c), the analytical model has to be manually simplified to reduce the number of meshes to about 5 million, which is a practically analyzable scale, so that the analytical model can be subjected to analysis.
Conventionally, simplification of such an analytical model has been performed by an operator using the analytical model, in which detailed meshes have been generated as shown in FIG. 21(b), as a template, and then modifying the shape. The simplification process of an analytical model has therefore been complex and a burden to the operator.
For example, the above VPS/Simulation-HUB has a function for removing minute parts and non-analysis object parts which do not affect the results of analysis using an object shape model in order to inhibit an increase in the mesh number. With this function, the number of meshes to be generated can be reduced by removal of unnecessary parts, which is smaller than the size designated by a user. In addition to the function, the art demands a technique to simplify an analytical model more effectively.